| Kabo Air | KO | QNK | |
| Kalahari Express | KEA | ||
| Kalingrad Air Enterprise | K8 | KLN | 097 |
| Kalitta Air | K4 | CKS | 272 |
| Kam Air | RQ | KMR | |
| Kampuchea Airlines | E2 | KMP | 837 |
| KAPO - Kazan Aviation | KAO | ||
| Karat | V2 | AKT | 501 |
| Karthago Airlines | 5R | KAJ | |
| Kavminvodyavia | KV | MVD | |
| Kazakhstan Airlines (Kazair) | K4 | KZA | 736 |
| Kazan Plant of Helicopters | KPH | ||
| KD Air Corporation | XC | KDC | |
| Kelowna Flightcraft Air Charter | KFA | ||
| Kendell Airlines | KD | KDA | 678 |
| Kent Aviation Services | KAH | ||
| Kenya Airways | KQ | KQA | 706 |
| Key Avia | KLV | ||
| Khalifa Airways | K6 | KWZ | |
| Khazar Airline | KHR | ||
| Khors Aircompany | X9 | KHO | 852 |
| Khyber Afghan Airlines | KHY | ||
| Kiev Aviation Plant | UAK | ||
| Kingfisher Airlines | IT | KFR | 090 |
| Kish Air | Y9 | IRK | 780 |
| Kitty Hawk Aircargo | KR | KHA | 798 |
| Kiwi International Airlines | KP | KIA | 538 |
| KLCuk | UK | UKA | 130 |
| KLM Cargo | KL | KLM | 074 |
| KLM City Hopper | KL | KLC | |
| KLM Exel | XT | AXL | 824 |
| KMV - Kavminvody Avia | MVD | ||
| Knighthawk Air Express | KNX | ||
| Kogalymavia | KGL | ||
| Kokshetau Airline | 0K | KRT | |
| Kolyma Avia Enterprise | KLI | ||
| Komiavia Air Enterprise | KMA | ||
| Komsomolsk na Amure | KNM | ||
| Korean Air | KE | KAL | 180 |
| Korsar Airlines | 6K | KRS | 557 |
| Kosmas Air | KMG | ||
| Kosmos Airlines | KSM | ||
| Kosova Airlines | KOS | ||
| Krai Aero Russian Austrian | KIO | ||
| KrasAir | 7B | KJC | 499 |
| Krilo Aviacompany Ltd | KRI | ||
| Kroonk Air Agency | KRO | ||
| KS Avia | KSA | ||
| Kuban Airlines | GW | KIL | 113 |
| Kulula.com | MN | CAW | 161 |
| Kumertau Express | |||
| Kurgan State Airline | |||
| Kursk State Air Enterprise | KUS | ||
| Kustani United Aviation Detachment | |||
| Kuwait Airways | KU | KAC | 229 |
| Kuzu Airlines Cargo | GO | KZU | 444 |
| Kyrgyzstan Airlines | K2 | KGA | 758 |